A lot of sun protection swimwear is skin tight so you can swim swiftly. The downside is that it can get a bit hot in warm climates, unless you soak it regularly. Also, when it stretches it looses some of its sun protection.
An alternative is a loose fitting hoodie. We've tested a Nike hoodie and breathable lightweight nylon shell pants in Thailand. Air temperature was about 35°C and the water of the lake was about 28°C warm. Sunshine was intense. The hoodie didn't feel hot, just cosy and snug.
The fabric is smooth on the outside and fluffy soft on the inside, feels good on the skin. It doesn't hold much water, but soaks up sweat and evaporates it quickly, keeping your skin fairly dry. The loose fit allows plenty of airflow. The hood can be used to protect your head from sunburn.
We tried these hoodies and tracksuit pants while trekking up a hot river valley. This got us a bit warm, but there were plenty of waterfalls to cool off. Once this outfit was wet it felt great, like wearable air-conditioning. However, it dried out soon so another "refill" was needed at the next waterfall.
Next we wore the hoodies and nylon shell pants on our way to the lake which took almost an hour by Tuc-Tuc (a motorised rickshaw, motorbike on the front, sofa on wheels in the back). The loose fit let a lot of wind through and felt really comfortable.
In the water the hoodie was just as comfortable as on land. It slows down your swimming a bit, but that is not a problem for recreational swimming. The hood comes in handy if the glare from the sun's reflections gets too intense. Just put it up, face away from the sun and you're cool.
After your swim the water runs off quickly leaving it just damp. If you keep it on in hot weather it will dry out in less than an hour. On cooler days you may want to wear a swim shirt underneath.
A wet hoodie creates awesome sound effects when the hood goes up on your head. It amplifies the sound around you like a big ear. You also hear the water inside your hoodie splashing around when you go swimming.
We feel this is sofar the most practical outfit for sun safety and UV protection. It has better circulation than a swimshirt, dries almost as fast and looks good both wet and dry.
Fabric: 71% Polyester, 29% Polybutylene Terepthalate (whatever that is)